The freeze-drying process of the nucleus of micafungin,a new generation of echinocinomycin antifungal drug, was studied. The moisture and impurity content, micafungin nucleus content as the optimizing index of the freeze-drying process, the effects of freezing temperature, freezing time and drying parameters on product quality were invest igated. The optimal freeze-drying conditions: the temperature and the time in the freezing stage are respectively -30℃ and 9 h, the vacuum temperature and the time in the primary drying stage are respectively 20 Pa, -20 ℃ are and 18 h, the vacuum, temperature and time in analytical drying stage are respectively 2 Pa, 10 ℃ and 3 h. 3 Batches of verifying test results under the optimal conditions show  that,the freeze-drying process is stable and the reproducibility is good.